Rapper DMX, who's serving 90 days in jail for animal abuse and theft, faces an assault charge following a tiff with a jail guard -- a legal problem that could send him to prison.

DMX, whose real name is Earl Simmons, was first put in Maricopa County Sheriff Joe Arpaio's Tent City jail after his January sentencing. Staff recently moved him to "lockdown" at the Towers jail in downtown Phoenix because he wouldn't stop swearing at guards, says Lisa Allen, spokeswoman for the sheriff's office.

In lockdown, inmates don't get the normal, disgusting gruel served to everyone else -- they get "Nutra-loaf," a gross slab of mystery food.

"I'm sure he was really hungry," says Allen. "When the detention officers went to pass out the evening meal on Sunday, he grabbed a meal that wasn't his."

When the officer told him to hand back the tray of regular food, DMX reportedly responded by throwing the tray and yelling, "Fuck you!"

"The officer was covered in slop," says Allen, referring to the food normally served to inmates.

Although the officer wasn't actually struck by DMX, the rapper's move against his jailers meets the definition of an assault, Allen says.

The question for DMX now is whether the new legal problem will mess with his probationary status. A probation violation could put DMX in prison for more than 10 years.

Michael Scerbo, spokesman for the Maricopa County Attorney's office, tells New Times he will check to see whether DMX's supervised probation has already begun and how a new criminal charge might affect the rapper.

UPDATE: Scerbo says DMX's probation began the day he was sentenced. The Maricopa County Adult Probation Department.